GPS: Garmin Etrex. Utterly confused

[arallsopp]

Ok. I'm normally a tech savvy kinda guy, but I am sure as hell borked by my Garmin GPS. I'm trying to set up a route for tomorrow, to get me from my house via Tower Bridge, to Manningtree, and another to get me back.

Here's what I'm doing.

Approach: Load Mapsource on PC. Create a new file. Add a waypoint for home, another for Manningtree station. Find route (set to delivery).

Result: It drags me up over crystal palace on the way into town with no reason. The route is longer, more complex, and hilly (not that the maps I'm using know this) than the one I'd take without the GPS.

Approach 2: Add waypoints that reflect my normal route (Bromley Hill, Brookmill Road, Evelyn Street) to get me into London the standard way. Recalculate.

Result: It works, but when I reverse the route to get me home, it sends me on a major detour of right turns across horrendous junctions to avoid the Catford gyratory (which is fine on a bike).

Approach 3: Add waypoints directly before and after the gyratory, shoe-horning it into shape.

Result: It works, both ways. Save the reversed route under a new name, and send route and waypoints to device. Device recalculates route, and sends me another way altogether once I get further along the route...

Approach 4: Convert routes to tracks using WinGDB. Send resulting tracks to device. See if 'Tracback' will guide me along the track

Result: Device recalculates track, then sends me via Dulwich which wasn't on either route previously.

I am now extremely confused. How the hell do I tell the device "I want to go to London, via the shortest route (Bromley Hill, Evelyn Street, etc) making sure I pass a couple of meet up points on the way, and don't feel obligated to pad out the remaining route with wild turns?"

Is it to do with "follow road"? Should I even be using routes? How the hell am I going to find my way to Edinburgh and back if I can't even get to London without saying "I'll ignore that bit and use local knowledge"

Oh dear. All a bit down today.



Should it matter, here are my specifics:

GPS: Garmin Etrex Legend HCx.
Maps: City Navigator Europe NT 2009 (unlocked)
PC: Garmin Mapsource 6.14.1 and 6.13, WinGDB v3.41

 

[Will1985]

I'm not familiar with the eTrex - are you able to create a route on mapmyride, bikely or gmap and then upload a crs or gpx file to the device (as I do with my 705)?

With the built in device mapping, I can also tell it to avoid certain types of road and think like a car or bike - is that possible?

 

[jimboalee]

I found to get the Legend to generate the most direct route on Topo GB, I had to put Avoids on every motorway on-ramp anywhere near where I intended to ride. This is done on Mapsource before the maps are loaded onto the unit.
Then I untoggled the 'Aviod Highways' on the unit.

For some strange reason, some 'A' Road dual carriageways are classed as 'Highways' by the writers.

I found this out many moons ago when the unit refused to go over the A46 Warwick by-pass at Stanks Island.

With the Aviod Highways toggled, it doesn't go on the motorways, but doesn't go on an unknown list of major 'A' roads either.

Around Urban Birmingham, it was fine - except for the lead-up road ( which is an 'A' road ) to the A38(M). Cycles are allowed on the lead-up road but Garmin wouldn't go on it.

Try playing with the 'Avoid' settings.

 

[MacB]

every time I read a GPS thread it puts me in doubt about whether to get one. I don't mind mapping routes but it does seem a long way from plug and play technology.

 

[arallsopp]

I'm not familiar with the eTrex - are you able to create a route on mapmyride, bikely or gmap and then upload a crs or gpx file to the device (as I do with my 705)?

With the built in device mapping, I can also tell it to avoid certain types of road and think like a car or bike - is that possible?

I can create routes then send them the the device as gpx tracks (once filtered). I've just tried asking it to 'tracback' along the track using "follow track" not "follow road" and that seems to work better. At the moment, I'm stuck at "Southeast to Turn1", but I suppose if I wander down the road I'll find out whether it plans to give me road names or anything later on. Jabbing it onto the second screen gives me a 'distance to next', 'speed' and compass point that might be very useful for guidance. If this approach works, its probably the best way for me to do things. Seems a pity that the workable solution doesn't use any of the routing capability of the map packs or device though..

I'll have a look through the device menus and see if i can set the vehicle type, etc, as maybe I can bring the proposed route and saved track closer together.

I found to get the Legend to generate the most direct route on Topo GB, I had to put Avoids on every motorway on-ramp anywhere near where I intended to ride. This is done on Mapsource before the maps are loaded onto the unit. Then I untoggled the 'Avoid Highways' on the unit. [...] With the Aviod Highways toggled, it doesn't go on the motorways, but doesn't go on an unknown list of major 'A' roads either.

Try playing with the 'Avoid' settings.

That could be a very handy tip. I'll look into that. I hadn't realised the 'avoid' routes were sent across to the device. I guess it just sends start / end points and then creates a route between them on the device afterwards, then avoids that. I know I messed up the first time I tried to avoid Blackwall tunnels as I drew Point A and B in the wrong order on the Southbound tunnel, and managed to set an avoidance area of much of docklands whilst the software desperately tried to find its way under the Thames, the wrong way on a one way street.

 

[arallsopp]

every time I read a GPS thread it puts me in doubt about whether to get one. I don't mind mapping routes but it does seem a long way from plug and play technology.

I know what you mean. Plug and pray seems to cover it right now, but I'm sure I'll get there*.

* 'There' is 'a point in time where I understand what the GPS will do'. I am hoping 'There' is a waypoint on the route to Manningtree, else tomorrow could be a long one.

 

[bonj2]

can you not work out the exact route yourself, and then put in enough way points to force it to calculate the exact route you want ... that's how i do it

 

[Greenbank]

every time I read a GPS thread it puts me in doubt about whether to get one. I don't mind mapping routes but it does seem a long way from plug and play technology.

That's why I program mine with sparse routes rather than tracks or viapoints/waypoints.

One routepoint where you'd have a routesheet instruction (i.e. only when you need to turn off a road, or where it'd be useful to have some prompting).

For example, this 239 point route http://www.bikely.com/maps/bike-path/143181 gets me from Putney to Padstow. The instructions of what to do at each point are encoded into the routepoint name.

I also don't have a mapping GPS, it's a basic yellow Garmin eTrex. Total cost under £100 and I didn't need to buy any maps or other software. You don't need maps if you're planning routes in advance.

I program it to tell me what I want it to tell me at every junction/road. Nothing more, nothing less. I've done 600km Audaxes with it with no problems, I got all the way from Putney up to North Berwick (750km) without having to look at a map, without getting lost and without having to stop once to check where I was and if I was still on the right roads.

You get used to the little tricks that you have to employ to get the GPS working as you want it. Until then it can be a little frustrating.

 

[arallsopp]

can you not work out the exact route yourself, and then put in enough way points to force it to calculate the exact route you want ... that's how i do it

Reading this in conjunction with Greenbank's comments below, I'm starting to see how that would work. At the moment, I'm still finding it hard to predict when the device and PC will vary on route interpretation, so suspect I'll shortly run up against the waypoint count limit if I'm having to play it safe.

Turning off routing all together, and laying out a broad track looks like it might work though. Whilst it feels like a step backward, I can see that adding a 'direct line' track that only features nodes on junctions (or where the road is indirect and confusing) will allow me to set up super long distance tracks. Careful naming (as shown in Greenbank's sample) would provide instructions at each deviation, and I could use the compass / distance to next instruction screen to keep me informed. Hmmmm... Wonder if the backlight turnson when I approach one? Anyone got experience here? Its not dark for 9 hours yet

That's why I program mine with sparse routes rather than tracks or viapoints/waypoints.

For the first time, I finally think I 'get' the purpose of routes and tracks.

• The 'route' feature gets used when I need the device to FIND a route for me. It'll run through its own calculations to find what it feels is the best approach, then will guide me along it with turn by turn directions, road names, distance to next turning, etc. I can add 50 places I'd like to see along the way, but it'll make up its own mind about how to get between them.
• The 'track' feature gets used when I already know the route I want to take, and I'm only using the GPS to ensure I stay on it. I can use up to 500 nodes to define each track, and the device will recognise when I pass each one, and provide an arrow in the direction of the next. If I want turn instructions, I have to name the trackpoints / nodes intelligently, or watch the arrow.

Anyone know if there's a way to find out what the next trackpoint will do? Does the backlight come on in advance, telling me its about to swing right by 30 degrees or will every node be a surprise unless encoded in the name?

On the plus side, I've only got to get to Tower Bridge, then I can use my tried and tested analogue GPS (keep my front wheel pointing at Aperitif's rear. Follow until hungry).

 

[bonj2]

For the first time, I finally think I 'get' the purpose of routes and tracks.

• The 'route' feature gets used when I need the device to FIND a route for me. It'll run through its own calculations to find what it feels is the best approach, then will guide me along it with turn by turn directions, road names, distance to next turning, etc. I can add 50 places I'd like to see along the way, but it'll make up its own mind about how to get between them.
• The 'track' feature gets used when I already know the route I want to take, and I'm only using the GPS to ensure I stay on it. I can use up to 500 nodes to define each track, and the device will recognise when I pass each one, and provide an arrow in the direction of the next. If I want turn instructions, I have to name the trackpoints / nodes intelligently, or watch the arrow.

Anyone know if there's a way to find out what the next trackpoint will do? Does the backlight come on in advance, telling me its about to swing right by 30 degrees or will every node be a surprise unless encoded in the name?

On the plus side, I've only got to get to Tower Bridge, then I can use my tried and tested analogue GPS (keep my front wheel pointing at Aperitif's rear. Follow until hungry).

Going by that differentiation, I only ever use "Tracks". i.e., I never use the routing algorithm in the actual machine. In creating those tracks I use the 'snap to road' feature in mapsource rather than 'straight lines', which presumably uses the routing algorithm of the software on the PC, but that then gets transferred to the unit as a track.
The only time I've ever used the routing algorithm in the machine is when I was cycling head long into a blizzard and wanted to go back west, so i just used the 'take me home' feature.

The only routing algorithm I've found to actually be any good for cycling is the one that viamichelin.com uses. All others, google included, appear to be crap. Google may have beautiful maps and be very fast, and all these fancy websites like bikely.com and mapmyride.com and what not may be very easy to use and easy to transfer data, and viamichelin is a bit slow and cumbersome, but they haven't got the algorithm that viamichelin's got!

Don't know about the etrex, haven't tested it yet - but the edge 605 had a screen which tells you how far it is to the next instruction and what that is. (iirc it's the one after the map mode when you press 'mode' to cycle through them).

 

[ColinJ]

I use the same method as Greenbank on my cheapo Etrex as well.

There's a good explanation of the technique here.

 

[samid]

I'm with bonj here - for auto-routing to be useful you need to add enough waypoints to coerce the device to take the route you want. My understanding is that with a dense net of roads as in the UK, and no obvious "shortcuts" like highways/motorways (which you cannot take on a bike), the complexity of route calculation grows very fast with distance between the points the GPS needs to connect. In my experience the route calculated by the GPS stops being reasonable when that distance grows above 50km or so, depending on the complexity of the roads of course. For instance, my GPS plotted me an absolutely crazy route from Slough to Milton Keynes, way longer than necessary, with loops going nowhere. OTOH the auto-calculated route from Morpeth to Edinburgh was absolutely fine because most of the way was on A1 which simplified route calculation significantly. Hence, adding enough waypoints enables the device to auto-calculate reasonable routes between them. Or at least that approach seems to work for me. (All that using Garmin City Navigator maps, on etrex Vista HCx.)

 

[jimboalee]

The way to use a Garmin eTrex or Edge.

1/ Only load the maps you NEED for the trip. I have a .gdb file which has the maps to cover 50 miles around my home. On these maps I have set 'Avoids' on all M-way on and off ramps.
If I am going on a Rando somewhere else, I build the route and use 'Select maps around route'. I set 'Avoids' on all M-way on and off ramps on those maps.
Delete my 'Home' maps off the unit and load the maps for the ride.

2/ DO NOT select 'Avoid Highway' or 'Avoid U-turns' on the unit.


The HCx eTrex and the Edge series have accomodation for 2Gbt of Micro SD. Many cyclists simply load the whole of Topo GB or City Navigator and go, without ANY avoids on M-way ramps. Garmin's instructions are very unclear as to what 'Highways' are and the user assumes they are M-ways in the UK. But NO, they are M-ways AND a lot of 'A' trunk roads and their junctions.

So if you have the entire City Navigator Europe loaded on 2 gbt card without any avoids, the unit will either direct you along M-ways in 'Car/Motorcycle'; or take you a long complicated route in 'Bicycle' down country lanes; or another long complicated route in 'Car/Motorcycle' - 'Avoid Highways'.

I use Metroguide Europe to construct Randos from Routesheet instructions because it is easier to identify the road junctions.

 

[dodgy]

You don't need 'avoids' if you're using City Navigator and a Garmin Edge. Topo is a piece of shoot, if you pardon my language

 

[jimboalee]

I have had no problems with Topo GB. I have set it up with avoids and it generates me routes between waypoints as good as ViaMichelin - 'By bike'.

IMHO, City navigator is the piece of shoot because you can't 'Show Profile' of the route before you ride it without 3rd Party 'contour packages'; and I wouldn't trust them as far as I could throw them.
City Navigator is for vehicles with internal combustion engines that aren't particularly bothered about hills.
I like to identify the climbs BEFORE the event and prepare for them.